Document and Entity Information (USD $)	0 Months Ended	12 Months Ended
	Feb. 23, 2015	Dec. 27, 2014	Feb. 23, 2015	Jun. 28, 2014
Document And Entity Information [Abstract]
Document Type		10-K
Amendment Flag		false
Document Period End Date		Dec. 27, 2014
Document Fiscal Year Focus		2014
Document Fiscal Period Focus		FY
Entity Registrant Name		SUMMIT MATERIALS, LLC
Entity Central Index Key		0001571371
Current Fiscal Year End Date		--12-27
Entity Well-known Seasoned Issuer		No
Entity Current Reporting Status		No
Entity Voluntary Filers		Yes
Entity Filer Category		Non-accelerated Filer
Entity Common Stock, Shares Outstanding		0
Membership interests percentage			100.00%
Membership interests description	As of February 23, 2015, 100% of the registrant’s outstanding limited liability company interests were held by Summit Materials Intermediate Holdings, LLC.
Entity Public Float				$ 0